1. Field of the Invention
This invention relates to a method of making a cutting tool.
2. Discussion of the Background
Cutting tools such as end mills are provided with a helically fluted working end. The helical flutes provide cutting edges for the tool. These cutting edges may be provided by abrasive compact which will typically be diamond or cubic boron nitride abrasive compact. Diamond abrasive compact is also known as PCD. Cubic boron nitride compact, is also known as PCBN.
Many methods are known in the art to produce the helical flutes of cutting tools with abrasive compact cutting edges. For example, U.S. Pat. No. 5,031,484 discloses a method of producing an end mill in which helical grooves are produced in a tool blank, the grooves are filled with a mixture of diamond powder and cobalt and then the blank subjected to elevated temperature and pressure conditions at which the diamond is crystallographically stable. Under these conditions, the diamond and cobalt form PCD in the groove and this PCD is bonded to the blank. A disadvantage of this method is that sintering of PCD or PCBN into a groove of a pre-sintered blank results in severe differential shrinkage between the PCD or PCBN phase and the pre-sintered blank. Therefore, the depth and possible geometries of the grooves are limited.
It is also possible to braze strips of PCD or PCBN to the helically fluted ends of such tools. Brazing, however, introduces weaknesses and severely limits the geometries possible.